This invention relates in general to processes for recovery of mercury from waste residues, and more particularly to a process for recovering mercury compounds from solutions containing nitric acid.
The prior art discloses numerous methods for recovery or removal of mercury from liquids, but none designed for this application. For example, Townsend U.S. Pat. No. 4,028,236, Gerow U.S. Pat. No. 3,802,910, Nolte U.S. Pat. No. 3,788,842, and Stenger U.S. Pat. No. 3,679,396 disclose various schemes for removal of elemental mercury. These work by means of amalgam formation with another metal.
Some prior art schemes for mercury removal, such as Hack U.S. Pat. No. 3,701,651, Cadmus U.S. Pat. No. 3,764,528 and Knepper U.S. Pat. No. 3,695,838 are restricted to non-acid solutions.
Kinoshita U.S. Pat. No. 4,057,423 teaches a process for removing mercury from sulfuric acid vapors. This process involves contacting acid vapor with metals having a reducing potential greater than that of mercury. The mercury is recovered from vapor phase sulfuric acid rather than from a liquid solution.